1 files changed, 230 insertions, 394 deletions

diff --git a/fs/afs/server.c b/fs/afs/server.c
index 44b0ce53e913..bde6125c2f22 100644
--- a/fs/afs/server.c
+++ b/fs/afs/server.c
@@ -1,6 +1,6 @@
 /* AFS server record management
  *
- * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
+ * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
  * Written by David Howells (dhowells@redhat.com)
  *
  * This program is free software; you can redistribute it and/or
@@ -11,127 +11,205 @@
 
 #include <linux/sched.h>
 #include <linux/slab.h>
-#include <rxrpc/peer.h>
-#include <rxrpc/connection.h>
-#include "volume.h"
-#include "cell.h"
-#include "server.h"
-#include "transport.h"
-#include "vlclient.h"
-#include "kafstimod.h"
 #include "internal.h"
 
-DEFINE_SPINLOCK(afs_server_peer_lock);
+unsigned afs_server_timeout = 10;       /* server timeout in seconds */
 
-#define FS_SERVICE_ID           1       /* AFS Volume Location Service ID */
-#define VL_SERVICE_ID           52      /* AFS Volume Location Service ID */
+static void afs_reap_server(struct work_struct *);
 
-static void __afs_server_timeout(struct afs_timer *timer)
+/* tree of all the servers, indexed by IP address */
+static struct rb_root afs_servers = RB_ROOT;
+static DEFINE_RWLOCK(afs_servers_lock);
+
+/* LRU list of all the servers not currently in use */
+static LIST_HEAD(afs_server_graveyard);
+static DEFINE_SPINLOCK(afs_server_graveyard_lock);
+static DECLARE_DELAYED_WORK(afs_server_reaper, afs_reap_server);
+
+/*
+ * install a server record in the master tree
+ */
+static int afs_install_server(struct afs_server *server)
 {
-        struct afs_server *server =
-                list_entry(timer, struct afs_server, timeout);
+        struct afs_server *xserver;
+        struct rb_node **pp, *p;
+        int ret;
+
+        _enter("%p", server);
 
-        _debug("SERVER TIMEOUT [%p{u=%d}]",
-               server, atomic_read(&server->usage));
+        write_lock(&afs_servers_lock);
+
+        ret = -EEXIST;
+        pp = &afs_servers.rb_node;
+        p = NULL;
+        while (*pp) {
+                p = *pp;
+                _debug("- consider %p", p);
+                xserver = rb_entry(p, struct afs_server, master_rb);
+                if (server->addr.s_addr < xserver->addr.s_addr)
+                        pp = &(*pp)->rb_left;
+                else if (server->addr.s_addr > xserver->addr.s_addr)
+                        pp = &(*pp)->rb_right;
+                else
+                        goto error;
+        }
 
-        afs_server_do_timeout(server);
-}
+        rb_link_node(&server->master_rb, p, pp);
+        rb_insert_color(&server->master_rb, &afs_servers);
+        ret = 0;
 
-static const struct afs_timer_ops afs_server_timer_ops = {
-        .timed_out      = __afs_server_timeout,
-};
+error:
+        write_unlock(&afs_servers_lock);
+        return ret;
+}
 
 /*
- * lookup a server record in a cell
- * - TODO: search the cell's server list
+ * allocate a new server record
  */
-int afs_server_lookup(struct afs_cell *cell, const struct in_addr *addr,
-                      struct afs_server **_server)
+static struct afs_server *afs_alloc_server(struct afs_cell *cell,
+                                           const struct in_addr *addr)
 {
-        struct afs_server *server, *active, *zombie;
-        int loop;
+        struct afs_server *server;
 
-        _enter("%p,%08x,", cell, ntohl(addr->s_addr));
+        _enter("");
 
-        /* allocate and initialise a server record */
         server = kzalloc(sizeof(struct afs_server), GFP_KERNEL);
-        if (!server) {
-                _leave(" = -ENOMEM");
-                return -ENOMEM;
+        if (server) {
+                atomic_set(&server->usage, 1);
+                server->cell = cell;
+
+                INIT_LIST_HEAD(&server->link);
+                INIT_LIST_HEAD(&server->grave);
+                init_rwsem(&server->sem);
+                spin_lock_init(&server->fs_lock);
+                server->fs_vnodes = RB_ROOT;
+                server->cb_promises = RB_ROOT;
+                spin_lock_init(&server->cb_lock);
+                init_waitqueue_head(&server->cb_break_waitq);
+                INIT_DELAYED_WORK(&server->cb_break_work,
+                                  afs_dispatch_give_up_callbacks);
+
+                memcpy(&server->addr, addr, sizeof(struct in_addr));
+                server->addr.s_addr = addr->s_addr;
         }
 
-        atomic_set(&server->usage, 1);
-
-        INIT_LIST_HEAD(&server->link);
-        init_rwsem(&server->sem);
-        INIT_LIST_HEAD(&server->fs_callq);
-        spin_lock_init(&server->fs_lock);
-        INIT_LIST_HEAD(&server->cb_promises);
-        spin_lock_init(&server->cb_lock);
-
-        for (loop = 0; loop < AFS_SERVER_CONN_LIST_SIZE; loop++)
-                server->fs_conn_cnt[loop] = 4;
+        _leave(" = %p{%d}", server, atomic_read(&server->usage));
+        return server;
+}
 
-        memcpy(&server->addr, addr, sizeof(struct in_addr));
-        server->addr.s_addr = addr->s_addr;
+/*
+ * get an FS-server record for a cell
+ */
+struct afs_server *afs_lookup_server(struct afs_cell *cell,
+                                     const struct in_addr *addr)
+{
+        struct afs_server *server, *candidate;
 
-        afs_timer_init(&server->timeout, &afs_server_timer_ops);
+        _enter("%p,"NIPQUAD_FMT, cell, NIPQUAD(addr->s_addr));
 
-        /* add to the cell */
-        write_lock(&cell->sv_lock);
+        /* quick scan of the list to see if we already have the server */
+        read_lock(&cell->servers_lock);
 
-        /* check the active list */
-        list_for_each_entry(active, &cell->sv_list, link) {
-                if (active->addr.s_addr == addr->s_addr)
-                        goto use_active_server;
+        list_for_each_entry(server, &cell->servers, link) {
+                if (server->addr.s_addr == addr->s_addr)
+                        goto found_server_quickly;
         }
+        read_unlock(&cell->servers_lock);
 
-        /* check the inactive list */
-        spin_lock(&cell->sv_gylock);
-        list_for_each_entry(zombie, &cell->sv_graveyard, link) {
-                if (zombie->addr.s_addr == addr->s_addr)
-                        goto resurrect_server;
+        candidate = afs_alloc_server(cell, addr);
+        if (!candidate) {
+                _leave(" = -ENOMEM");
+                return ERR_PTR(-ENOMEM);
         }
-        spin_unlock(&cell->sv_gylock);
 
-        afs_get_cell(cell);
-        server->cell = cell;
-        list_add_tail(&server->link, &cell->sv_list);
+        write_lock(&cell->servers_lock);
 
-        write_unlock(&cell->sv_lock);
+        /* check the cell's server list again */
+        list_for_each_entry(server, &cell->servers, link) {
+                if (server->addr.s_addr == addr->s_addr)
+                        goto found_server;
+        }
+
+        _debug("new");
+        server = candidate;
+        if (afs_install_server(server) < 0)
+                goto server_in_two_cells;
 
-        *_server = server;
-        _leave(" = 0 (%p)", server);
-        return 0;
+        afs_get_cell(cell);
+        list_add_tail(&server->link, &cell->servers);
+
+        write_unlock(&cell->servers_lock);
+        _leave(" = %p{%d}", server, atomic_read(&server->usage));
+        return server;
+
+        /* found a matching server quickly */
+found_server_quickly:
+        _debug("found quickly");
+        afs_get_server(server);
+        read_unlock(&cell->servers_lock);
+no_longer_unused:
+        if (!list_empty(&server->grave)) {
+                spin_lock(&afs_server_graveyard_lock);
+                list_del_init(&server->grave);
+                spin_unlock(&afs_server_graveyard_lock);
+        }
+        _leave(" = %p{%d}", server, atomic_read(&server->usage));
+        return server;
+
+        /* found a matching server on the second pass */
+found_server:
+        _debug("found");
+        afs_get_server(server);
+        write_unlock(&cell->servers_lock);
+        kfree(candidate);
+        goto no_longer_unused;
+
+        /* found a server that seems to be in two cells */
+server_in_two_cells:
+        write_unlock(&cell->servers_lock);
+        kfree(candidate);
+        printk(KERN_NOTICE "kAFS:"
+               " Server "NIPQUAD_FMT" appears to be in two cells\n",
+               NIPQUAD(*addr));
+        _leave(" = -EEXIST");
+        return ERR_PTR(-EEXIST);
+}
 
-        /* found a matching active server */
-use_active_server:
-        _debug("active server");
-        afs_get_server(active);
-        write_unlock(&cell->sv_lock);
+/*
+ * look up a server by its IP address
+ */
+struct afs_server *afs_find_server(const struct in_addr *_addr)
+{
+        struct afs_server *server = NULL;
+        struct rb_node *p;
+        struct in_addr addr = *_addr;
 
-        kfree(server);
+        _enter(NIPQUAD_FMT, NIPQUAD(addr.s_addr));
 
-        *_server = active;
-        _leave(" = 0 (%p)", active);
-        return 0;
+        read_lock(&afs_servers_lock);
 
-        /* found a matching server in the graveyard, so resurrect it and
-         * dispose of the new record */
-resurrect_server:
-        _debug("resurrecting server");
+        p = afs_servers.rb_node;
+        while (p) {
+                server = rb_entry(p, struct afs_server, master_rb);
 
-        list_move_tail(&zombie->link, &cell->sv_list);
-        afs_get_server(zombie);
-        afs_kafstimod_del_timer(&zombie->timeout);
-        spin_unlock(&cell->sv_gylock);
-        write_unlock(&cell->sv_lock);
+                _debug("- consider %p", p);
 
-        kfree(server);
+                if (addr.s_addr < server->addr.s_addr) {
+                        p = p->rb_left;
+                } else if (addr.s_addr > server->addr.s_addr) {
+                        p = p->rb_right;
+                } else {
+                        afs_get_server(server);
+                        goto found;
+                }
+        }
 
-        *_server = zombie;
-        _leave(" = 0 (%p)", zombie);
-        return 0;
+        server = NULL;
+found:
+        read_unlock(&afs_servers_lock);
+        ASSERTIFCMP(server, server->addr.s_addr, ==, addr.s_addr);
+        _leave(" = %p", server);
+        return server;
 }
 
 /*
@@ -140,347 +218,105 @@ resurrect_server:
  */
 void afs_put_server(struct afs_server *server)
 {
-        struct afs_cell *cell;
-
         if (!server)
                 return;
 
-        _enter("%p", server);
-
-        cell = server->cell;
+        _enter("%p{%d}", server, atomic_read(&server->usage));
 
-        /* sanity check */
-        BUG_ON(atomic_read(&server->usage) <= 0);
-
-        /* to prevent a race, the decrement and the dequeue must be effectively
-         * atomic */
-        write_lock(&cell->sv_lock);
+        ASSERTCMP(atomic_read(&server->usage), >, 0);
 
         if (likely(!atomic_dec_and_test(&server->usage))) {
-                write_unlock(&cell->sv_lock);
                 _leave("");
                 return;
         }
 
-        spin_lock(&cell->sv_gylock);
-        list_move_tail(&server->link, &cell->sv_graveyard);
-
-        /* time out in 10 secs */
-        afs_kafstimod_add_timer(&server->timeout, 10 * HZ);
-
-        spin_unlock(&cell->sv_gylock);
-        write_unlock(&cell->sv_lock);
+        afs_flush_callback_breaks(server);
 
-        _leave(" [killed]");
+        spin_lock(&afs_server_graveyard_lock);
+        if (atomic_read(&server->usage) == 0) {
+                list_move_tail(&server->grave, &afs_server_graveyard);
+                server->time_of_death = get_seconds();
+                schedule_delayed_work(&afs_server_reaper,
+                                      afs_server_timeout * HZ);
+        }
+        spin_unlock(&afs_server_graveyard_lock);
+        _leave(" [dead]");
 }
 
 /*
- * timeout server record
- * - removes from the cell's graveyard if the usage count is zero
+ * destroy a dead server
  */
-void afs_server_do_timeout(struct afs_server *server)
+static void afs_destroy_server(struct afs_server *server)
 {
-        struct rxrpc_peer *peer;
-        struct afs_cell *cell;
-        int loop;
-
         _enter("%p", server);
 
-        cell = server->cell;
-
-        BUG_ON(atomic_read(&server->usage) < 0);
-
-        /* remove from graveyard if still dead */
-        spin_lock(&cell->vl_gylock);
-        if (atomic_read(&server->usage) == 0)
-                list_del_init(&server->link);
-        else
-                server = NULL;
-        spin_unlock(&cell->vl_gylock);
-
-        if (!server) {
-                _leave("");
-                return; /* resurrected */
-        }
-
-        /* we can now destroy it properly */
-        afs_put_cell(cell);
-
-        /* uncross-point the structs under a global lock */
-        spin_lock(&afs_server_peer_lock);
-        peer = server->peer;
-        if (peer) {
-                server->peer = NULL;
-                peer->user = NULL;
-        }
-        spin_unlock(&afs_server_peer_lock);
-
-        /* finish cleaning up the server */
-        for (loop = AFS_SERVER_CONN_LIST_SIZE - 1; loop >= 0; loop--)
-                if (server->fs_conn[loop])
-                        rxrpc_put_connection(server->fs_conn[loop]);
-
-        if (server->vlserver)
-                rxrpc_put_connection(server->vlserver);
+        ASSERTCMP(server->fs_vnodes.rb_node, ==, NULL);
+        ASSERTCMP(server->cb_promises.rb_node, ==, NULL);
+        ASSERTCMP(server->cb_break_head, ==, server->cb_break_tail);
+        ASSERTCMP(atomic_read(&server->cb_break_n), ==, 0);
 
+        afs_put_cell(server->cell);
         kfree(server);
-
-        _leave(" [destroyed]");
 }
 
 /*
- * get a callslot on a connection to the fileserver on the specified server
+ * reap dead server records
  */
-int afs_server_request_callslot(struct afs_server *server,
-                                struct afs_server_callslot *callslot)
+static void afs_reap_server(struct work_struct *work)
 {
-        struct afs_server_callslot *pcallslot;
-        struct rxrpc_connection *conn;
-        int nconn, ret;
-
-        _enter("%p,",server);
-
-        INIT_LIST_HEAD(&callslot->link);
-        callslot->task = current;
-        callslot->conn = NULL;
-        callslot->nconn = -1;
-        callslot->ready = 0;
-
-        ret = 0;
-        conn = NULL;
-
-        /* get hold of a callslot first */
-        spin_lock(&server->fs_lock);
-
-        /* resurrect the server if it's death timeout has expired */
-        if (server->fs_state) {
-                if (time_before(jiffies, server->fs_dead_jif)) {
-                        ret = server->fs_state;
-                        spin_unlock(&server->fs_lock);
-                        _leave(" = %d [still dead]", ret);
-                        return ret;
+        LIST_HEAD(corpses);
+        struct afs_server *server;
+        unsigned long delay, expiry;
+        time_t now;
+
+        now = get_seconds();
+        spin_lock(&afs_server_graveyard_lock);
+
+        while (!list_empty(&afs_server_graveyard)) {
+                server = list_entry(afs_server_graveyard.next,
+                                    struct afs_server, grave);
+
+                /* the queue is ordered most dead first */
+                expiry = server->time_of_death + afs_server_timeout;
+                if (expiry > now) {
+                        delay = (expiry - now) * HZ;
+                        if (!schedule_delayed_work(&afs_server_reaper, delay)) {
+                                cancel_delayed_work(&afs_server_reaper);
+                                schedule_delayed_work(&afs_server_reaper,
+                                                      delay);
+                        }
+                        break;
                 }
 
-                server->fs_state = 0;
-        }
-
-        /* try and find a connection that has spare callslots */
-        for (nconn = 0; nconn < AFS_SERVER_CONN_LIST_SIZE; nconn++) {
-                if (server->fs_conn_cnt[nconn] > 0) {
-                        server->fs_conn_cnt[nconn]--;
-                        spin_unlock(&server->fs_lock);
-                        callslot->nconn = nconn;
-                        goto obtained_slot;
+                write_lock(&server->cell->servers_lock);
+                write_lock(&afs_servers_lock);
+                if (atomic_read(&server->usage) > 0) {
+                        list_del_init(&server->grave);
+                } else {
+                        list_move_tail(&server->grave, &corpses);
+                        list_del_init(&server->link);
+                        rb_erase(&server->master_rb, &afs_servers);
                 }
+                write_unlock(&afs_servers_lock);
+                write_unlock(&server->cell->servers_lock);
         }
 
-        /* none were available - wait interruptibly for one to become
-         * available */
-        set_current_state(TASK_INTERRUPTIBLE);
-        list_add_tail(&callslot->link, &server->fs_callq);
-        spin_unlock(&server->fs_lock);
-
-        while (!callslot->ready && !signal_pending(current)) {
-                schedule();
-                set_current_state(TASK_INTERRUPTIBLE);
-        }
-
-        set_current_state(TASK_RUNNING);
-
-        /* even if we were interrupted we may still be queued */
-        if (!callslot->ready) {
-                spin_lock(&server->fs_lock);
-                list_del_init(&callslot->link);
-                spin_unlock(&server->fs_lock);
-        }
-
-        nconn = callslot->nconn;
-
-        /* if interrupted, we must release any slot we also got before
-         * returning an error */
-        if (signal_pending(current)) {
-                ret = -EINTR;
-                goto error_release;
-        }
-
-        /* if we were woken up with an error, then pass that error back to the
-         * called */
-        if (nconn < 0) {
-                _leave(" = %d", callslot->errno);
-                return callslot->errno;
-        }
-
-        /* were we given a connection directly? */
-        if (callslot->conn) {
-                /* yes - use it */
-                _leave(" = 0 (nc=%d)", nconn);
-                return 0;
-        }
+        spin_unlock(&afs_server_graveyard_lock);
 
-        /* got a callslot, but no connection */
-obtained_slot:
-
-        /* need to get hold of the RxRPC connection */
-        down_write(&server->sem);
-
-        /* quick check to see if there's an outstanding error */
-        ret = server->fs_state;
-        if (ret)
-                goto error_release_upw;
-
-        if (server->fs_conn[nconn]) {
-                /* reuse an existing connection */
-                rxrpc_get_connection(server->fs_conn[nconn]);
-                callslot->conn = server->fs_conn[nconn];
-        } else {
-                /* create a new connection */
-                ret = rxrpc_create_connection(afs_transport,
-                                              htons(7000),
-                                              server->addr.s_addr,
-                                              FS_SERVICE_ID,
-                                              NULL,
-                                              &server->fs_conn[nconn]);
-
-                if (ret < 0)
-                        goto error_release_upw;
-
-                callslot->conn = server->fs_conn[0];
-                rxrpc_get_connection(callslot->conn);
+        /* now reap the corpses we've extracted */
+        while (!list_empty(&corpses)) {
+                server = list_entry(corpses.next, struct afs_server, grave);
+                list_del(&server->grave);
+                afs_destroy_server(server);
         }
-
-        up_write(&server->sem);
-
-        _leave(" = 0");
-        return 0;
-
-        /* handle an error occurring */
-error_release_upw:
-        up_write(&server->sem);
-
-error_release:
-        /* either release the callslot or pass it along to another deserving
-         * task */
-        spin_lock(&server->fs_lock);
-
-        if (nconn < 0) {
-                /* no callslot allocated */
-        } else if (list_empty(&server->fs_callq)) {
-                /* no one waiting */
-                server->fs_conn_cnt[nconn]++;
-                spin_unlock(&server->fs_lock);
-        } else {
-                /* someone's waiting - dequeue them and wake them up */
-                pcallslot = list_entry(server->fs_callq.next,
-                                       struct afs_server_callslot, link);
-                list_del_init(&pcallslot->link);
-
-                pcallslot->errno = server->fs_state;
-                if (!pcallslot->errno) {
-                        /* pass them out callslot details */
-                        callslot->conn = xchg(&pcallslot->conn,
-                                              callslot->conn);
-                        pcallslot->nconn = nconn;
-                        callslot->nconn = nconn = -1;
-                }
-                pcallslot->ready = 1;
-                wake_up_process(pcallslot->task);
-                spin_unlock(&server->fs_lock);
-        }
-
-        rxrpc_put_connection(callslot->conn);
-        callslot->conn = NULL;
-
-        _leave(" = %d", ret);
-        return ret;
 }
 
 /*
- * release a callslot back to the server
- * - transfers the RxRPC connection to the next pending callslot if possible
+ * discard all the server records for rmmod
  */
-void afs_server_release_callslot(struct afs_server *server,
-                                 struct afs_server_callslot *callslot)
+void __exit afs_purge_servers(void)
 {
-        struct afs_server_callslot *pcallslot;
-
-        _enter("{ad=%08x,cnt=%u},{%d}",
-               ntohl(server->addr.s_addr),
-               server->fs_conn_cnt[callslot->nconn],
-               callslot->nconn);
-
-        BUG_ON(callslot->nconn < 0);
-
-        spin_lock(&server->fs_lock);
-
-        if (list_empty(&server->fs_callq)) {
-                /* no one waiting */
-                server->fs_conn_cnt[callslot->nconn]++;
-                spin_unlock(&server->fs_lock);
-        } else {
-                /* someone's waiting - dequeue them and wake them up */
-                pcallslot = list_entry(server->fs_callq.next,
-                                       struct afs_server_callslot, link);
-                list_del_init(&pcallslot->link);
-
-                pcallslot->errno = server->fs_state;
-                if (!pcallslot->errno) {
-                        /* pass them out callslot details */
-                        callslot->conn = xchg(&pcallslot->conn, callslot->conn);
-                        pcallslot->nconn = callslot->nconn;
-                        callslot->nconn = -1;
-                }
-
-                pcallslot->ready = 1;
-                wake_up_process(pcallslot->task);
-                spin_unlock(&server->fs_lock);
-        }
-
-        rxrpc_put_connection(callslot->conn);
-
-        _leave("");
-}
-
-/*
- * get a handle to a connection to the vlserver (volume location) on the
- * specified server
- */
-int afs_server_get_vlconn(struct afs_server *server,
-                          struct rxrpc_connection **_conn)
-{
-        struct rxrpc_connection *conn;
-        int ret;
-
-        _enter("%p,", server);
-
-        ret = 0;
-        conn = NULL;
-        down_read(&server->sem);
-
-        if (server->vlserver) {
-                /* reuse an existing connection */
-                rxrpc_get_connection(server->vlserver);
-                conn = server->vlserver;
-                up_read(&server->sem);
-        } else {
-                /* create a new connection */
-                up_read(&server->sem);
-                down_write(&server->sem);
-                if (!server->vlserver) {
-                        ret = rxrpc_create_connection(afs_transport,
-                                                      htons(7003),
-                                                      server->addr.s_addr,
-                                                      VL_SERVICE_ID,
-                                                      NULL,
-                                                      &server->vlserver);
-                }
-                if (ret == 0) {
-                        rxrpc_get_connection(server->vlserver);
-                        conn = server->vlserver;
-                }
-                up_write(&server->sem);
-        }
-
-        *_conn = conn;
-        _leave(" = %d", ret);
-        return ret;
+        afs_server_timeout = 0;
+        cancel_delayed_work(&afs_server_reaper);
+        schedule_delayed_work(&afs_server_reaper, 0);
 }